Ruzin this is a proposal to obtain NIH funding for a Carl Zeiss LSM710 laser scanning confocal microscope for the CNR Biological Imaging Facility (BIF). This microscope system will augment the research and training capabilities of the BIF, and specifically, will permit the research of the eight (8) Major Users listed in this proposal to proceed forward with their funded research. The BIF is the starting point for biological research involving optical microscopy for a great many researchers at UC Berkeley. A major limitation, however, is the inability to resolve dim fluorescence do FRAP experiments, and/or long-term time-lapse fluorescence imaging using confocal microscopy due to the limitations of the existing 10-year old LSM510 META confocal microscope. The requested instrument will fill a much-needed gap in optical instrumentation in the College of Natural Resources, the College of Letters and Sciences, and the general scientific community at the University of California, Berkeley. Over the last year we performed preliminary experiments on eight biological systems, comparing the results obtainable using a demo Zeiss LSM710 confocal microscope to that obtained using the BIF's LSM510 confocal microscope. For each project we present evidence showing that the LSM710 microscope far surpasses the capabilities of our existing Zeiss LSM510 in sensitivity and resolution. The researchers described in this proposal are involved in myriad aspects of microbial and eukaryotic biological events;all of which require higher sensitivity confocal microscopy to adequately visualize their particular biological questions. The research described in this proposal involves fluorescence visualization of: (1) bacteria (Coates, Fleiszig, Koleili, Lindow), Drosophila chromosomes (Botchan), multi-layered mammalian acini (Luo), podosome acting in T3T cells (Martin), RNA granules in dendrites (Napoli), and the yeast nuclear pore complex (Weis). Together these projects represent the breadth of confocal imaging that is necessary for the Biological Imaging Facility at UC Berkeley.